The present application is a continuation of International Application No. PCT/SE01/00886, filed on Apr. 25, 2001, in the English language, the disclosure of which is incorporated by reference herein.
The present invention relates to a rechargeable breathing apparatus with a closed breathing system, in particular for aqua divers and smoke divers, comprising a breathing bellows for receiving the exhaled air, which is connected, by means of a hydrostatic valve, to a pressurized gas container, and which bellows is arranged to deliver breathing air to the diver subsequent to removal of CO2 and addition of O2.
Breathing devices for diving in water may be divided into three main groups, open, closed, and semi-closed systems. In open systems, the inhalation is made from a pressurized bottle, and the exhalation is made directly to the surrounding water. The drawbacks are that unconsumed oxygen gas is breathed directly into the water. During deep-sea diving the air source has to be replaced during the descent and ascent, in order for the diver not to suffer from poisoning or lack of oxygen. The system is relatively noisy; it has a high acoustic profile, and emits air bubbles. Further, it demands a surface organization, with access to a compressor or pressurized bottles. The advantage is the relative simplicity of the system.
Closed and semi-closed systems involve purification of the exhaled air from carbon dioxide in a container with, for example, calcium hydroxide. The purified gas then continues to a breathing sack, where new oxygen gas is added from a pressurized bottle. It is also possible to add new inert gas from an inert gas-bottle, in order to compensate for any increase in depth. The drawbacks are the complexity and vulnerability of the system for dosage and monitoring, the toxicity of the calcium hydroxide, and the fact that it is a consumable substance that has to be replaced after each dive. Pressurized oxygen entails risk of fire or explosion. This system too, demands an extensive surface organization, with ability to supply calcium hydroxide, pressurized oxygen, and inert gas. The advantages of a closed system is that the system does not generate any bubbles and has a low noise level, and that there is no need for gas replacement when descending and ascending during deep-sea diving. The advantages with a semi-closed system are that it produces less bubbles than an open system, and that it has a low noise level. The disadvantage is the difficulty to control the oxygen partial pressure, and the large surface organization needed in order to provide mixed gas and calcium hydroxide.
One of the objects of the present invention is to provide a breathing apparatus which:
should be rechargeable,
is dependent only on a minimal surface organization,
can remain operative during long periods of time.
has a simple construction and is robustly built,
lacks sensitive electronic components,
utilizes exclusively reliable mechanical gauges for monitoring, the function of which are unimportant for the function of the system as such,
has a low weight,
maintains the oxygen partial pressure relatively constant at low pressures,
alternatively maintains PO2 within a narrow interval,
has a low noise level and is bubble free at a constant depth,
is associated with a very low risk of fire or explosion, and which
counteracts an increase in PO2 during descent/fall.
In accordance with the present invention, these and other objects have now been realized by the invention of a rechargeable breathing apparatus including a closed breathing system for receiving exhaled air containing carbon dioxide and supplying breathing air therefrom, the apparatus comprising means for adsorbing CO2 from the exhaled air, a breathing bellows for receiving the exhaled air and delivering the breathing gas, and an oxygen accumulator connected to the bellows, the oxygen accumulator containing a reversably oxygen fixating agent and being rechargeable by bringing the reversably oxygen fixating agent into reaction with oxygen or air whereby the oxygen is fixated thereto. In a preferred embodiment, the apparatus includes a pressurized gas container for a predetermined gas, and means for hydrostatic cooperation between the breathing bellows and the pressurized gas container. In a preferred embodiment, the apparatus is adapted for use by an aqua diver or a smoke diver.
In accordance with one embodiment of the rechargeable breathing apparatus of the present invention, the apparatus includes a temperature control element in connection with the oxygen accumulator. Preferably, the temperature control element comprises a heating or cooling element.
In accordance with another embodiment of the rechargeable breathing apparatus of the present invention, the reversably oxygen fixating agent comprises a metal complex, and preferably a metallic complex such as cobalt-bis-salicylaldehyde-ethylene-diimine (Salcomine), cobalt-bis-3-fluoro-salicylaldehyde-ethylene-diimine (Fluomine), and cobalt-bis-3-ethoxy-salicylaldehyde-ethylene-diimine.
In accordance with another embodiment of the rechargeable breathing apparatus of the present invention, the reversably oxygen fixating agent comprises a metal complex such as a cobalt phorfyrin.
In accordance with another embodiment of the rechargeable breathing apparatus of the present invention, the reversably oxygen fixating agent comprises a simple inorganic salt.
In accordance with another embodiment of the rechargeable breathing apparatus of the present invention, the apparatus includes a chamber surrounding the oxygen accumulator, and a carbon dioxide absorber connected to the chamber.
In accordance with another embodiment of the rechargeable breathing apparatus of the present invention, the oxygen accumulator includes at least one outlet, and the apparatus includes a particle filter connected to the at least one outlet, and a water vapor absorbing filter connected to the at least one outlet.
In accordance with one embodiment of the apparatus of the present invention, the predetermined gas can be helium, air or another diveable gas.
In accordance with another embodiment of the apparatus of the present invention, the apparatus includes an air pump connected to the pressurized gas container, preferably a manually operable air pump.